Re: [Taler] Taler issue with Nix

[Fedi Jamoussi]

Thank you for the swift reply, Christian.

Indeed, we did add the exchange to the merchant's config:

[merchant-exchange-test]
CURRENCY=KUDOS
EXCHANGE_BASE_URL=http://exchange:8081/
MASTER_KEY=2TQSTPFZBC2MC4E52NHPA050YXYG02VC3AB50QESM6JX1QJEYVQ0

Which reminds me that I forgot to include its config file previously since it 
was on a different VM (oops), but I'll add it here.

> Note that I'm not exactly sure that this is something Nix packages _should_ 
> configure automatically

You're right and this is not set by default by the module. Rather, it's only 
configured for the purpose of the test, which is also the case for the account 
and instance registrations and the keys.

Best Regards,
Fedi


Sent with Proton Mail secure email.

On Tuesday, September 10th, 2024 at 6:52 PM, Christian Grothoff 
<grothoff@gnunet.org> wrote:

> Dear Fedi,
>
> Pardon me for not having looked at your configurations, but I have one
> nagging suspicion: did you add the exchange to the merchant
> configuration as a trusted exchange?
>
> For example, by default we include a configuration file 'kudos.conf':
>
> $ cat kudos.conf
> # Trust Taler project for "KUDOS" currency so that demos work out-of-the-box
> [merchant-exchange-kudos]
> EXCHANGE_BASE_URL = https://exchange.demo.taler.net/
> MASTER_KEY = "F80MFRG8HVH6R9CQ47KRFQSJP3T6DBJ4K1D9B703RJY3Z39TBMJ0"
> CURRENCY = KUDOS
>
> which enables that specific exchange with that specific master public
> key to the list of exchanges this merchant will accept funds from. If
> you did not add the exchange you set up locally, well, then the merchant
> will tell the wallets that it doesn't trust that exchange, and then
> wallets will not consider that exchange when trying to pay the merchant
> --- and IIRC you should see basically that exact error message.
>
> Anyway, if that is not the case, we'll need to dig a bit deeper, but
> this seems the most likely explanation. Note that I'm not exactly sure
> that this is something Nix packages should configure automatically, as
> which exchanges one does business with beyond those that are shipped
> with the packages is intended to be a manual decision by each merchant.
> So this could well be a case of "need to improve documentation" and not
> "need to fix packaging" ;-).
>
> Happy hacking!
>
> Christian
>
> On 9/10/24 6:14 PM, Fedi Jamoussi via Taler wrote:
>
> > Dear GNU Taler developers,
> >
> > My name is Fedi Jamoussi (@eljamm https://github.com/eljamm) and I'm a
> > Summer of Nix https://github.com/ngi-nix/summer-of-nix 2024
> > participant working with (@Atemu https://github.com/Atemu) on
> > packaging Taler with Nix. Everything has been progressing smoothly since
> > starting this endeavor, but we've recently run into a bit of a roadblock
> > and we're hoping you can help us solve it.
> >
> > So far, the core Taler components have already been packaged
> > successfully in nixpkgs and have been recently updated to version 0.13
> > https://github.com/NixOS/nixpkgs/pull/338184. Currently, we are
> > working on a NixOS module https://github.com/NixOS/nixpkgs/pull/332699
> > which will make setting up these components much easier and which
> > already supports configuring the exchange, libeufin-{bank,nexus} and the
> > merchant.
> >
> > To showcase the capabilities of the module and provide an example of how
> > it's configured, we've also made a NixOS test
> > https://github.com/NixOS/nixpkgs/blob/5a2a5aa3d700f795daa77d69451f06d4e4917a7c/nixos/tests/taler/basic.nix
> >  where each component runs separately in a VM to simulate a real-world 
> > scenario in which multi-machine interactions are happening.
> >
> > In this test, we're registering the services' accounts and instances,
> > making a currency withdrawal to the CLI wallet and then using those
> > coins to pay for a merchant's order.
> >
> > The issue here is that the wallet is unable to pay for the order and
> > instead prints an /"insufficient balance"/ message, even though the
> > funds have been successfully withdrawn and are available. However, this
> > doesn't happen when using the online bank https://bank.demo.taler.net
> > and exchange https://exchange.demo.taler.net demos with the same
> > wallet and merchant.
> >
> > As such, this leads me to believe that something is wrong or missing in
> > the configuration of these two components or in how they're handling the
> > transaction. There might also have been a step that we missed to make
> > the wallet's funds spendable.
> >
> > In this regard, I hope the attached document
> > https://drive.proton.me/urls/2C675D921C#Wdi92BXuXZGB, which contains
> > the logs and configs, will help shed some light on the issue at hand and
> > if you need any further information, I'll be happy to provide it.
> >
> > That said, I'm unfortunately nearing the limit of hours I have left in
> > the SoN program, but I'd really like to solve this issue and have a
> > fully-working basic example by that time. If we can accomplish this,
> > then perhaps the NixOS module can accompany Taler's launch as an easy
> > way to configure and test the program.
> >
> > Thank you for the amazing work that you're doing. We're looking forward
> > to your support.
> >
> > --
> > Best Regards,
> > Fedi Jamoussi

merchant-taler.conf
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